Personal status physiologic monitor system and architecture and related monitoring methods

ABSTRACT

A method for performing context management, said method comprising the steps of: producing a continuous physiologic signal, as detected by a monitoring device; associating at least one unique hardware identifier to said continuous physiologic signal and binding a unique patient identifier to said continuous signal wherein a change in said physiologic signal in which said signal is no longer continuous will cause the unique patient identifier to unbind from said signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 11/031,736, now (U.S. Pat. No. 7,382,247), filed Jan. 7, 2005,which is a continuation application under 35 U.S.C. §120 claimingbenefit of U.S. Ser. No. 10/806,770, filed Mar. 22, 2004, which is anon-provisional patent application claiming priority under 35 U.S.C.§119 (e)(1) to U.S. Ser. No. 60/456,609, filed, Mar. 21, 2003, entitled“Personal Status Physiologic Monitor System and Architecture” and U.S.Ser. No. 60/554,706, filed Mar. 20, 2004, entitled “Personal StatusPhysiologic Monitor System and Architecture and Related MonitoringMethods”, the contents of each of which are herein incorporated in theirentirety.

FIELD OF THE INVENTION

This invention relates generally to patient monitoring systems, and morespecifically to an improved patient monitoring system architecture.

BACKGROUND OF THE INVENTION

Over 1.1 million Americans experience a cardiac arrest each year. Ofthat number about 500,000 die, or about twice the number that die fromany other cause, including accidents. Approximately half of theseincidents occur within the hospital.

The first 4-6 minutes from the onset of cardiac arrest to treatment arecrucial in obtaining a successful outcome. Therefore early detection, orbetter anticipation of the event is critical in positively impactingpatient outcomes. Traditional methods for early detection are too costlyto be broadly deployed. Current methods include continuous monitoringwithin the hospital setting through either fixed intensive caremonitoring or ambulatory telemetry monitoring. The capital cost ofcurrent technology is approximately $12,000 to $30,000 per device andrequires high technical skill levels to use the devices and relatedsystems effectively.

Continuous vital signs monitoring systems are well known to thoseskilled in the art. Hospitals have broadly adopted such systems in theearly 1960s as intensive care units emerged as a standard of care. Theseearly systems utilized proprietary network connectivity from a pluralityof bedside monitors to a central viewing station. Early systems werebased on both hardwired analog and digital communications methods. Thesesystems migrated to standards based IEEE 802.3 Ethernet-based digitalcommunications systems in the 1980s, as Ethernet technologies maturedand became cost effective to implement. Hardwired systems expanded inthe hospital as medical care subspecialties grew, but were generallyrestricted to intensive care settings.

Concurrent with the development and growth of hardwired systems, one-waytelemetry systems were created that allowed ECG monitoring of patientsduring ambulation. Early systems emerged from NASA development in theearly '60s for monitoring of astronauts. Simple analog radios operatingin the unused VHF and UHF spectrum with simple modulation schemes grewin coronary care step-down units. These systems operated under Part 15of the FCC Rules in unused portions of the television spectrum.

Telemetry technology improved with one-way digital communications in the1980s. Additional parameters were added, first by Siemens in addingblood oxygen saturation (SPO₂) and then by others in the late 1980s.

In 1992 Welch, et al., patented for the first time a system that allowedcentral surveillance monitoring to be decoupled from intensive care orcoronary care step down environments. This patent, U.S. Pat. No.5,319,363, allowed central surveillance to be accessible to any bedsidelocation without dedicating devices to these beds. The '363 patentfurther provided for both two-way hardwired and wireless communicationsmethods. Protocol Systems, Inc., later acquired by Welch Allyn, Inc. ofSkaneateles, N.Y., commercialized this invention.

In terms of other known prior art, Dempsey, U.S. Pat. Nos. 5,579,001,5,579,775 and 5,687,734 each describe a two-way telemetry apparatus thatuses a backchannel receiver to carry control signals between aproprietary wireless network and a bedside monitor. Additionally,Dempsey further describes a system apparatus that combines traditionalone-way medical telemetry and traditional one-way (opposite) pagingsystems to achieve bi-directional communications. Flach, et al., U.S.Pat. Nos. 5,767,791 and 5,748,103, describe a combined bidirectionaltelemetry system that optimizes available bandwidth with modulationschemes such as frequency hopping. VitalCom, later acquired by GEMedical Systems, has since commercialized the subject matter describedby this latter patent.

West, et al., U.S. Pat. Nos. 6,544,173 and 6,544,174, improved upon theWelch '363 patent describing a two-way standards based wireless patientmonitor and system that provides connectivity to a plurality of centralstations in an enterprise wide real-time monitoring network. The Westpatents also describe a patient wearable device that can be configuredin either a connected state or a non-connected state.

Besson et al., U.S. Pat. No. 5,682,803, describes a wireless two-waysensor with error correcting means that can be used to control andmanipulate the data communicating between a patch electrode and abedside monitor. Besson's intent was to eliminate the wires betweensensors and bedside monitors.

DeLuca, U.S. Pat. No. 6,440,067B1, describes a system that includes bodyworn sensors communicating to a body worn repeater which in turncommunicates to a base station for transmission over a telephone line orinternet to a central review station. DeLuca's device is designed forthe monitoring of physical activity that is associated with a specific“non-communicating” activity.

All of the above known references, and others as referenced that arereferenced by these patents, commonly describe a real time, continuousphysiologic monitoring system. The devices described by each of thesepatents are intended to be in a continuous connected state whenconfigured with an associated system. The consequence of thisrequirement is a network that requires sufficient power to support acontinuously connected instrument. Therefore, for wireless connectivity,sufficiently sized batteries must be incorporated in order to achieveacceptable useful life for the combined apparatus.

The above noted '803 Besson patent and its progeny is especially awareof this requirement and teaches means for powering wireless sensors tosupport the sensor and the wireless link. Besson et al. further provideserror correcting means, as well as control and manipulation of thecommunications data, in order to achieve high data throughput quality atminimum RF power levels. DeLuca also recognizes this limitation andprovides for recharging means for his described body-worn sensors.

Therefore, there is a general need in the field for a low cost, simpleto use diagnostic monitoring device. The potential market for such adevice goes well beyond the more than 61 million Americans who areclassified as having some form of cardiovascular disease. The USmilitary is also actively investigating personal status monitoring forits deployed military personnel. Military sources estimate an annualvolume of 40,000 units. It is a therefore primary object of the presentinvention to address the above-noted need in the diagnostic field.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is disclosed asystem for actively monitoring a patient, said system comprising:

at least one body-worn monitoring device, each said at least onebody-worn monitoring device including at least one sensor capable ofmeasuring at least one physiologic parameter and detecting at least onepredetermined event;

at least one intermediary device linked to said at least one body-wornmonitoring device by at least one network; and

at least one respondent device linked to said at least one intermediarydevice by at least one network and programmed to perform a specifiedfunction automatically when said predetermined event is realized.According to at least one embodiment, at least one of the at least onebody-worn monitoring device, at least one intermediary device and atleast one respondent device is programmed to perform a specific functionautomatically when the predetermined event occurs, without userintervention. For example, the at least one respondent device can beprogrammed to contact emergency services upon occurrence of thepredetermined event.

According to another aspect of the present invention, there is discloseda system for actively monitoring a patient, said system comprising:

at least one body-worn monitoring device, each said at least onebody-worn monitoring device including at least one sensor capable ofmeasuring at least one physiologic parameter and detecting at least onepredetermined event;

at least one intermediary device linked to said at least one body-wornmonitoring device by at least one network;

at least one computer linked to at least one intermediary device by atleast one network; and

at least one respondent device linked to said at least one computerthrough at least one network, at least one of the body-worn monitoringdevice, said at least one intermediary device and said at least onerespondent device being programmed to perform a specified functionautomatically when said predetermined event is realized. The computercan, for example, be a server that can also permit transmission ofcontrol algorithms through the at least one network to the body-wornmonitoring device for event detection.

According to yet another aspect of the present invention, there isprovided a system for actively monitoring a patient, said systemcomprising:

at least one body-worn monitoring device, each said at least onebody-worn monitoring device including at least one sensor capable ofmeasuring at least one physiologic parameter and detecting at least onepredetermined event;

at least one intermediary device linked to said at least one body-wornmonitoring device by means of a first wireless network; and

at least one respondent device linked to said at least one intermediarydevice by a second wireless network wherein at least one of thebody-worn monitoring device, said at least one intermediary device andsaid at least one respondent device is programmed to perform a specifiedfunction automatically when said predetermined event is realized. In oneembodiment, the first wireless network is a local low-power personalarea network and the second wireless network is a wide area network orequivalent.

According to yet another aspect of the present invention, there isdescribed a system for actively monitoring a patient, said systemcomprising:

at least one body-worn monitoring device, each said at least onebody-worn monitoring device including at least one sensor capable ofmeasuring at least one physiologic parameter and detecting at least onepredetermined event;

at least one intermediary device linked to at least one body-wornmonitoring device through a first wireless network; and

and at least one respondent device linked to said at least oneintermediary device through a second wireless network, wherein at leastone of said at least one body-worn monitoring device, said at least oneintermediary device and said at least one respondent device isprogrammed to perform a specified function automatically when saidpredetermined event is realized.

According to still another aspect of the present invention, there isdisclosed a system for actively monitoring a patient, said systemcomprising:

at least one body-worn monitoring device, each said at least onebody-worn monitoring device including at least one sensor for measuringat least one physiologic parameter and detecting at least onepredetermined event;

at least one intermediary device lined to said at least one body-wornmonitoring device by means of a first wireless network;

at least one computer linked to said at least one intermediary device bya second wireless network; and

at least one respondent device linked to said at least one computer bysaid second wireless network, at least one of said at least onebody-worn monitoring device, said at least one intermediary device andsaid at least one respondent device being programmed to perform aspecified function automatically when said predetermined event isrealized.

According to yet still another aspect of the present invention, there isdisclosed a system for communicating data, said system comprising:

at least one monitoring device, said at least one monitoring devicehaving at least one sensor for continuously measuring at least onephysiologic parameter and detecting at least one predetermined event;

at least one network linking said at least one monitoring device to atleast one respondent device wherein said at least one network isnormally operatively in a first state where the network is off exceptwhen periodic data is transmitted, said network having a second statewhere data is transmitted upon said at least one predetermined eventhaving occurred. The periodic data can be compressed data or portions ofa measured physiologic data stream.

According to yet another aspect of the present invention, there isdisclosed a method for performing patient to device context management,said method comprising the steps of:

producing a physiologic signal, as detected by a monitoring device;

associating a unique monitoring device identifier to a unique patientidentifier; and

appending said unique patient identifier to said continuous physiologicsignal, wherein a change in said physiologic signal in which said signalis no longer continuous will cause the unique patient identifier todisassociate from said signal.

According to still another aspect of the present invention, there isdisclosed a method for performing patient to environment contextmanagement comprising the steps of:

producing a continuous physiologic signal, as detected by a monitoringdevice;

associating a unique monitoring device identifier to a unique patientidentifier;

appending said unique patient identifier to said continuous physiologicsignal; and

associating a unique location device identifier to at least one uniquemonitoring device identifier, thereby associating a patient location toat least one unique patient identifier.

According to yet another aspect of the present invention, there isdisclosed a system for actively monitoring a patient, said systemcomprising:

at least one ECG monitoring device;

at least one computer for receiving data from said ECG monitoringdevice; and

at least one network linking said at least one ECG monitoring device andsaid at least one computer in which said at least one ECG monitoringdevice transmits all the R-R intervals to said at least one computerregardless of whether said at least one ECG monitoring device istransmitting ECG waveforms or not.

According to still another aspect of the present invention, there isdisclosed a method for balancing power consumption, sensitivity andspecificity in detecting physiologic events, said method comprising thesteps of:

determining the power consumption as a function of sensitivity andspecificity for each computational element of the -system;

arranging the computational flow from the most power sensitive of saidcomputational elements to the least power sensitive of saidcomputational elements;

setting the sensitivity of the first computational element to allowdetection of all events; and

sending the events detected along with an associated at least onewaveform by the first computational element to the second computationalelement; setting the sensitivity of the second computational element toidentify at least some of the false positive detections received fromsaid first computational element.

It is believed that the presently disclosed system architecturedistinguishes itself from that of the prior art by uniquely utilizingtwo-way radio and technology and advanced signal processing. Thisarchitecture is based on a communications network that is predominantlyin an “off” state when the at least one predetermined event has notoccurred. That is, there is no requirement for continuous monitoringoutside of the physiologic sensors. This innovation permits thepresently described system to share wireless network resources withother applications without the need to install dedicated wirelessnetwork equipment. The system which can preferably include, for example,at least one body-worn personal status monitoring device, communicatesto an intermediary personal gateway device that is also preferablypatient-worn and uses a WiFi, IEEE 802.11b, or other emergingstandards-based radio network (such as, for example, IEEE 802.11a orIEEE 802.11g) that is already installed in the facility, or communicatesto a respondent device such as a cellular phone or at least one otherrespondent device using TDMA, CDMA, GSM, G3 or other WAN (Wide AreaNetwork) communications technologies.

Preferably, the personal status monitoring device of the presentinvention contains advanced signal processing algorithms that aredesigned to detect events, rather than continuously streamingpatient-related vitals data over the wireless networks. A beacon usingthe same wireless communications means as is used to transferphysiologic data on the personal status monitoring device maintains aconnectivity status that is independent of event driven transmission.Embedded in the beacon are vital signs status data and signal processingdata that can efficiently reconstruct significant information sensed bythe at least one physiologic sensor. The data representation ispreferably be lossy (as opposed to the lossless forms that are presentlyfound in the current art). Alternatively, the embedded beacon maycontain a subset of the physiologic data necessary to maintain acontinuous record, such as, but not limited to heart rate and R to Rintervals, depending in part on data compression capabilities that arecontained within the personal status monitoring device.

Advantageously, the personal status monitoring device of the presentinvention is preferably designed to achieve low purchasing costs and asa result may not contain sufficient processing power to complete thesignal analysis function that would be required for medical personnelinterpretation. Therefore, signal processing is preferably distributedthroughout the herein described system. By distributed, it is meant thatthe personal status monitoring device is highly sensitive in its eventidentification. Additional signal processing algorithms and patternrecognition may then be embedded in at least one intermediary device(e.g., a personal gateway device, and/or central server) and/orrespondent devices for the purpose of reducing false alarms and reducingdata to that of useful clinical information wherein the sensitivity isadjusted in each succeeding device to identify false positive detectionsreceived therefrom.

To Applicants' best knowledge, it is believed that there are no existingsystems known that provide system features as described by the presentinvention. That is to say, existing all known WLAN systems used formedical monitoring are used in a continuous “ON” state in which data iscontinually or continuously transmitted through the system regardless ofthe condition of the patient. Existing WLAN non-medical systems are notused for event based surveillance monitoring with a beacon feature inorder to maintain connectivity status. It is believed that no systemused today provides lossy physiologic data reduction in order to achievelow power consumption for communications. Furthermore, it is believedthat no existing system provides distributed signal processing andpattern recognition in order to optimize low power and normally “OFF” orquiet communications optimization.

An advantage of the present invention is that the unique networkarchitecture features described-herein preserves battery life byminimizing the use of any wireless (e.g., RF) links between at least onepersonal status monitoring device and at least one intermediary device(such as a personal gateway device according to the preferredembodiment), as well as between the at least one intermediary gatewaydevice and the wireless network infrastructure. This feature allows themonitoring and intermediary (e.g., gateway or other) devices to embedsmaller batteries, such as, for example, those found in digital wristwatches, and therefore smaller packages that lend themselves to lowercost platforms can be more integrated into a normal patient activitylevel.

A further essential advantage of the present invention is that theubiquity permits the personal status monitoring device of the presentinvention to assume other functions, such as, for example, contextmanagement. By context management, it is meant that the binding of apatient or other type of unique identifier that can be embedded into thepersonal status monitoring device of the present invention uponinstallation of same on the patient's body can also be used for positiveidentification of the patient, independent of the device's primarypersonal status monitoring function. Healthcare workers can thereforequery the personal status monitoring device for patient identificationwith the same respondent device used for event monitoring.

Additionally, the system permits other forms of context management, forexample, between the patient and the environment in order to associatepatient location with a patient identifier.

These and other objects, features and advantages will become readilyapparent to those of sufficient skill when read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simple diagrammatic view of the primary components of anevent monitoring system in accordance with a preferred embodiment of thepresent invention;

FIG. 2 is a diagrammatic view of a preferred system/network architectureof the present invention;

FIG. 3 is a schematic diagram of a personal status monitoring devicecomponent of the system depicted in FIGS. 1 and 2;

FIG. 4 is a schematic hardware diagram of a preferred personal gatewayor intermediary device component of the system/network shown in FIGS. 1and 2 of the present invention;

FIG. 5 is a schematic software diagram of the personal gateway device ofFIG. 4; and

FIG. 6 depicts a schematic diagram employing the presently describedsystem as used in a health care facility or similar environment.

DETAILED DESCRIPTION

The following description relates to an event monitoring systemsarchitecture according to a preferred embodiment of the presentinvention. Certain terms are used throughout the discussion, such as,for example, “top”, “bottom”, “upper”, “lower” and the like in order toprovide a convenient frame of reference with regard to the accompanyingdrawings. These terms, however, unless specifically indicated otherwise,are not intended to be over limiting of the present invention.

Throughout the course of the discussion, various terms are used thatrequire additional definitions for clarity.

By “body-worn device,” it is meant that the device is entirely worn onthe body of the patient wherein the device is affixed or otherwiseattached directly to the skin of the patient.

“Network” refers to a communications linkage between at least twodevices. Unless stated otherwise, this linkage can be wireless orhardwired in nature or both.

A “patient-worn” device refers to a device that is carried by or isattached to a patient. A patient-worn device according to thisdefinition can include but is not limited to a “body-worn” device.

An “intermediary device” refers to a device such as a relay radio link,a computer or other apparatus that is disposed between at least onepatient monitoring device and at least one respondent device.

“Respondent device” refers to a device that is notified of apredetermined event in accordance with the present system. Therespondent device can be a cellular phone, a computer, or other devicethat can further be enabled to be accessed by a user to gain access tothe present system, request data, input patient-related data and otherfunctions.

In brief, the present invention is a systems solution for the earlydetection and communication of life threatening physiologic events toappropriate first responders. Referring to FIG. 1, the fundamentalarchitecture of the herein described system includes four (4) primarycomponents:

-   -   1) at least one low cost, ultra-low power (e.g., long battery        life), easy to use personal, body-worn status monitoring device        10 that is attached directly to the patient;    -   2) at least one wireless, battery powered, intermediary or        personal gateway device 20 that is patient-worn, such as on the        arm, a belt or otherwise disposed. The at least one personal        gateway device 20 according to this particular architecture is        used to relay events, signals, and information, preferably        bi-directionally between the attached personal status monitoring        device 10 and a central server 30;    -   3) a central server 30 that provides a plurality of database        management, rule sets, advanced signal processing and display        rendering, with regard to the above noted system components, as        well as information routing to at least one respondent device;        and    -   4) at least one respondent device 40 that displays pertinent        information regarding patient status. Additional details        relating to each of these system components is provided below.

Referring to FIG. 2, the wireless connectivity architecture of thepresent embodiment that includes the above primary system components ispreferably defined by two separate wireless networks; namely:

i) a low power Wireless Personnel Area Network (WPAN) 24 having aneffective range of about 1-10 meters; and

ii) a medium/long range wireless network 28 that is preferably based ona Wireless Local Area Network (WLAN) technology (e.g., IEEE 802.11x), aWireless Area Network (WAN) (e.g., cellular phone networks) or both.

It should be noted that the above system construction is preferred forthe sake of power consumption and feasability. It should be pointed out,however, that there are many variations that can be utilized herein. Forexample, according to one variation, the server can be removed in favorof an arrangement that includes a personal status monitoring device, anintermediary device such as a computer and a respondent device in whichthe respondent device is configured in the manner of a computer.According to yet another variation, the intermediary device can beentirely removed from the system and a single wireless network can beutilized in lieu of the two separate wireless networks described herein.Similarly and for reasons described below, the system is notspecifically limited necessarily exclusively to the use of wirelessnetworks. That is, some hard wired connections could be contemplatedwithin the inventive concepts herein.

Still referring to FIG. 2, the present monitoring system is defined by adistributed hardware, networked and logical architecture leveraging lowcost, broadly applied technologies. As previously noted, the four (4)major or primary components of the present system/network architectureincludes at least one personal status monitoring device 10; at least onepersonal gateway or intermediary device 20 a, 20 b, 20 c; at least onecentral server 30 a, having a database 30 b; and at least one respondentdevice 40 a, 40 b. The intermediary or gateway device 20 can be abody-worn device such as shown in 20 a, a PDA 20 b, a cellular phone 20c, or other similar device acting predominantly as a radio intermediaryor relay to the server 30 a, such as a PAN to TCP/UDP translator.

The server 30 a can be provided in a separate connection to otherdevices such as a laptop computer 6 a, an IBM or other. compatiblecomputer 6 b and at least one printer 6 c such as through an Ethernetconnection there with as found in a healthcare facility. At least onerespondent device is represented by a cellular phone 40 a and a PDA 40 bthough other devices such as a computer can be utilized. As shown, theWAN 28(b) provides a server 30 a input for home use of the patientstatus monitoring device 10 via the local network 24 through anintermediary device (cellular phone 20 c).

A fundamental assumption of the present monitoring system is that eachof the herein described central server 30 a, the intermediary devices 20a, 20 b, 20 c and the respondent devices 40 a, 40 b and therefore thesystem as a whole, normally is predominantly in an “off” or “quiet”state, in spite of the fact that the at least one personal statusmonitoring device 10 may be continuously sampling physiologic signalsfrom the patient as well as environmental signals, and is processingthese signals for specific events. The use of this “quiet” state is indirect contrast with traditional hospital based continuous monitoringsystems and is an essential feature of the herein described system.

Additionally, patient context management is an essential task of theherein described system that is effectively managed through the at leastone personal status monitoring device 10. In brief, a unique hardware(HW) ID 209, 524, FIGS. 3, 4, respectively, of each of the gatewaydevice and the patient status monitoring device are associated with aunique patient identifier 206, FIGS. 3, 4, respectively, and this uniquepatient identifier is then appended to the continuous physiologic signalas detected by the personal status monitoring device 10 that istransmitted to the at least one personal gateway device 20 a, 20 b, and20 c, thereby creating a binding relationship. This “binding”relationship exists for as long as the personal status monitoring device10 maintains a positive continuous physiologic signal relationship withthe patient. Any disruption in continuous signal recognition for aprescribed length of time will result in an “unbound” state that willremove the unique patient identifier from the patient status monitoringdevice 10.

In a preferred form, each of the personal status monitoring device 10and the personal gateway device 20 are first synched to one another.This synching can occur either on the patient or not. Hardware IDs 209,524 (shown in FIGS. 3, 4, respectively) for each of the two devices 10,20 are then transmitted to the central server 30 a and the uniquepatient identifier 206 is created and transmitted for storage by thepersonal status monitoring device 10 and for appending to the measuredphysiologic signal. Similarly, the intermediary or gateway device 20 canalso store the unique patient identifier 206. This appended patientidentifier 206 is found in each transmission data packet transmitted bythe radio of the patient status monitoring device as a periodic beacon.The unique patient identifier 206 is an unique number or other symboland therefore not the name of the patient. Unbinding of this identifier206, caused for example by the monitoring device inadvertently detachingfrom the patient, will then disable same, for example, from being usedby another patient.

With the preceding overview providing cursory background, a moredetailed description is made with regard to each of the above primarysystem components, starting with the personal status monitoring device10. Referring to FIGS. 2 and 3, the personal status monitoring device 10is a patient wearable device, and is preferably encapsulated in a singleflexible covering 14. This device 10 is preferably self-contained andincludes a plurality of components, including a plurality of electrodesand/or physiologic sensors that are integrated into the highly flexiblecovering 14 for attachment directly to the skin of the patient, therebymaking the device “body-worn”. Personal status monitoring devices 10, asnoted below, may contain one or more instrumentation applicationsdepending on the desired measurement(s). Such measurements can include,but are not limited to, ECG, acoustics, tissue and blood oxygen levels,blood chemistry, surface or body temperature, and accelerometry (e.g.,patient movement or determination of patient orientation) with eachapplication being designed for low power utilization. For example andaccording to one application, a plurality of personal status monitoringdevices 10, each having unique functionality with regard to a particularpatient, can be positioned on the patient simultaneously at any numberof locations that optimize physiologic signal acquisition. Theselocations may or may not be immediately proximate to one another on thepatient.

Referring to FIG. 3, an appropriate schematic diagram of a preferredembodiment of the personal status monitoring device 10 is depicted. Inthe present embodiment that is described throughout, the personal statusmonitoring device 10 includes a disposable ECG electrode assembly,though it should be realized that the device can include both disposableas well as reusable or semi-reusable (e.g., single patient)instrumentation assembly in whole or at least in part. According to thisfigure, the ECG assembly includes a pair of ECG electrodes 50 a,b thatare connected to an analog ECG front end 103, the front end preferablyincluding pacemaker detection, such as is generally known to those inthe art. The physiologic and measuring parameters of the patient-wornstatus monitoring device 10 described herein include one channel of ECGmeasurement using two or three or more electrode configurations. Twoelectrodes are shown according to this embodiment, as well as oneadditional channel of acoustic signal and one additional channel ofaccelerometry, having respective front ends 104, 105. Additionally, thepersonal status monitoring device 10 further includes scalability,thereby permitting additional channels, such as for determining otherparameters including but not limited to body temperature, pulseoximetry, patient location and/or other parameters to be added. The ECGfront end 103 is connected to a multiplexer 205 that samples ECG as wellas other signals integrated into the personal status monitoring device10. Alternatively, a plurality of AID converters may be used. In thecase in which only one ECG vector is measured by the personal statusmonitoring device 10 only, the multiplexer 205 would not be required.

An A/D converter 201 converts the analog signal from the various sensorsand electrodes into digital values for manipulation, and analysis by acontained microcontroller 202. The Propaq 100 series vital signs monitormanufactured by Welch Allyn, Inc., for example, serves as one referencedesign. All or some of these components may be integrated into a singleintegrated systems semiconductor, as is found in many families ofmicrocontrollers. The microcontroller 202 in turn may also be availableon the radio semiconductor, such as an ASIC chip.

The microcontroller 202 further provides the features of signalprocessing, as well as feature and event extraction of the ECG signalfor wireless relay through an RF radio transceiver 300 to acorresponding RF antenna 301 to the intermediary gateway device 20, FIG.1 via the first wireless network 24, FIG. 1. The microcontroller 202, RFradio transceiver 300 and RF antenna 301 may be a single semiconductoror alternatively can be designed as individual components. Furthermore,the microcontroller 202 can alternatively be divided into twomicrocontrollers; that is, a first microcontroller (not shown) forinstrumentation data acquisition and reduction, and a secondmicrocontroller (not shown) used only for radio communications. Afurther design permits one-way or two-way (e.g., bi-directional)communications with the first and second microcontrollers.

Still referring to FIG. 3, non-volatile memory device 203 and volatilememory device 204 may be integrated into the microcontroller 202 or beseparately provided. Non-volatile memory device 203 preferably includesa re-writable memory component, such as FLASH or a similarly utilizedtechnology, and a non-rewritable memory component, such as PROM(Programmable Read Only Memory), for the storage of data andconfiguration information, such as patient name, ID, care plan, and/orother information that is specifically and categorically unique to thepatient as described below. Input of any or portions of this informationand data may be entered either though the RF antenna 301 and RF radiotransceiver 300 noted above, an RFID antenna 303 and an RFID radiotransceiver 302 or through a separate input/output I/O port 110.

The presently defined system is versatile and anticipates many differentforms of patient identification. For example, patient identification inhealthcare hospital practice typically includes a unique alphanumericnumber that is printed onto a wrist strap or similar type of braceletthat is worn by the patient during their hospital stay. Some hospitals,alternatively or in combination, place bar codes on these straps formachine readability. Yet another alternative method of patientidentification is to embed a low cost RFID device directly into thewrist strap. The present system architecture is designed to transferthis information, regardless of the manner of patient identification,either through an auxiliary detection device (e.g. a bar code scanner(not shown) having a radio transmitter that is compatible with thepersonal status monitoring device 10 or directly, as in the case of anembedded RFID tag on the same patient as that of the personal statusmonitoring device 10. The auxiliary detection device can further beconnected indirectly with the server 30 in the network, for example viathe personal gateway device 20.

In addition to patient identification, a unique device or hardwareidentification is stored in non-volatile memory device 203, this storagebeing done preferably at the time of manufacture and being done in thenon-rewritable memory component thereof. In terms of labeling,appropriate regulatory labels are utilized. Moreover, a clearly visibleunique product identifier (e.g., serial number) is also preferablyencoded in machine and human readable formats (such as, for example, barcode) on the exterior of the personal status monitoring device 10.

Data storage can generally be accomplished in the personal statusmonitoring device 10 as follows:

First, once respective hardware IDs 209, 524, FIGS. 3, 4, respectively,and a patient ID have initially been established at the device level(e.g., the gateway device/personal status monitoring device interface),each of these are transmitted to the server 30 and a unique patientidentifier 206 is created. This identifier 206 is relayed via the WLAN28 to the gateway device 20 and then to the personal status monitoringdevice 10 for storage. This storage, unlike the hardware identificationoccurs in the non-volatile memory device within the re-writable memorycomponent thereof. As a result of the preceding, no encryption isrequired of patent data subsequently transmitted in that the uniquepatient identifier 206 is known only to the server 30.

Derived sensor data is also stored into the nonvolatile memory devices203 of the microcontroller 202 of the personal status monitoring device10. This data includes a sample (e.g., on the order of approximately6-12 seconds) of digitized waveform data, as well as storage of selectedcompressed data.

As noted, context management is an essential task of the personal statusmonitoring device 10. Fusion occurs between the hardware ID 209, 524,FIGS. 3, 4, respectively, the unique patient identifier 206, and thederived sensor data (e.g., a continuous physiologic signal) whereindecay or removal of fusion in absence of continuous sensor data causesthe binding of the patient identifier 206 to cease. Absence ofcontinuous sensor data can occur in a number of different ways, forexample, when the battery of the personal status monitoring device 10 islow or dead, when the intermediary gateway device 20 is out of rangefrom the personal status monitoring device 10 in the personal areanetwork 24, when electrode leads from the personal status monitoringdevice 10 have come loose or have detached from the patient, or based ona specific command of the central server 30.

Still referring to FIG. 3, a number of optional sensors 56 can also beconnected to the microcontroller 202 of the personal status monitoringdevice 10 for additional functionality. In addition, a number ofoptional actuators can also be added thereto. These actuators contain anumber of output functions such as and including visual annunciation107, audio annunciation 108 and/or user actuation 109 that can also beconnected in like manner. These annunciators 107, 108, 109 can be usedfor a variety of purposes including, but not limited to, deviceoperation and state indication, alarm and/or alert event, user attentionindication, and user request for attention, among others.

Optional means associated with the personal status monitoring device 10are further provided for the recharging of an embedded battery 102 bthrough mechanical, inductive, or thermal charging mechanisms 102 a,such as those presently found, for example, in digital watches via apower supply circuit 102 a. In the instance in which portions of thepersonal status monitoring device 10 are disposable, some or all ofthese recharging means 102 a, may not be necessarily required and adisposable battery can be utilized.

Still referring to FIG. 3, a series of amplifiers located in front ends103, 104, 105, 106 may preferably include selectable or tunable filtersfor the removal of environmental or other unwanted signals. Moredetailed discrete circuits may alternatively be utilized in lieu of theamplifiers 103 as is commonly known in the field and require no furtherdiscussion herein. Provisions for the control of the amplifiers 103,104, 105, 106 are provided through ports (not shown) that are providedon the contained microcontroller 202. As previously stated, otherbiomedical signals may also be included in the same or similar path toprovide similar functionality herein-described of the device 10.

As noted above and in addition to the ECG electrode assembly an acousticchannel is provided, whereby any predetermined number of acousticaltransducers, for example, electret or piezo or other suitable sensors52, can be used to in order detect audible biomedical signals formeasurement and event detection and transmission. In addition andaccording to this embodiment, an accelerometry channel is also providedthat includes at least one accelerometer 54 for measuring patientmovement for determining body orientation, activity and critical events,such as an unexpected fall. Sensitive three-axis accelerometers may alsobe incorporated into the flexible covering 14 of the monitoring device10 for mechanically detecting heart beats on the surface of the chest orrespiration rate through low frequency chest wall motion. Otherbiomedical measurements may be suitably added, such as tissue and bloodoxygen levels, as low power instrumentation solutions become available.These additional measurements can be formed either internal to theoverall package or on the flexible covering 14.

At least one patient location sensor (not shown) can be additionallyintegrated into the personal status monitoring device 10 by leveragingthe network infrastructure with the radio technology as is generallyknown to those skilled in the art of IEEE 802.15.4 technology or otherlocation technologies, such as those offered by Radianse Corp.Radiolocation technology can therefore be fused to patientidentification in order to provide unique patient location withinfacilities that are equipped with this capability.

As noted above, one primary purpose of the herein-described system is tocontinuously monitor the status of the person to which a personal statusmonitoring device is attached based on one or more physiologic signalsand to detect when one or more of these signals is outside a settablethreshold value. A first embodiment of the present system detects theheartbeat, and using the detected heartbeat computes a heart rate.Life-threatening arrhythmias (LTAs) can therefore be detected on abody-worn monitoring device. Three methods are anticipated in thedetection of a heartbeat: an ECG channel, the auscultatory (audio)channel, and/or the accelerometry channel.

In order to improve both the sensitivity and specificity of heartbeatdetection, the audio channel is also preferably provided in addition tothe ECG channel. This audio channel may also be used to detect otherphysiologic events, such as breathing. Alternatively or in combinationwith the audio channel and the ECG channel, the at least oneaccelerometer 54 may be used to detect mechanical motion on the bodysurface. The use of three or more channels, each with differentmeasurement methods, will improve the overall reliability of the eventdetermination but stay within the resource limits of the containedmicrocontroller 202.

The embodiment herein described includes only ECG sensing with regard toa specific patient-triggered event or events for purposes of triggeringthe respondent device(s) 40. At least one event detecting algorithm isstored within the microprocessor 202 of the personal status monitoringdevice 10 is set to high sensitivity, though preferably the systemfurther relies upon additional signal processing and pattern recognitionwithin each of the personal gateway device 20 and/or the central server30 for true positive qualifications prior to finally triggering the atleast one respondent device 40 a, 40 b. It should be readily apparentthat new techniques in signal processing are anticipated. For example,the audio channel may also be used for the detection of certaincatastrophic events, as would be of interest in a threateningenvironment such as the military. The addition of the accelerometrychannel also provides the capability of measuring environmental events,for example, such as exercise, or perhaps more significantly, when thepatient falls accidentally or otherwise. This latter feature is ofspecific interest in healthcare facilities where patient falls are asignificant adverse event and are costly. The accelerometer 54 also maybe used to detect high motion artifacts and be used to control filterson the ECG and/or audio channels or turn these channels off such thatfalse alarms due to motion artifacts are not passed through to at leastone of the respondent devices 40, 40 b. It will be readily apparent thatthese and other sensor fusion methods are possible within the ambits ofthe overall system architecture as indicated by the capability foradditional input channels described herein.

In addition to event detection, the herein-described personal statusmonitoring device 10 supports a periodic wireless beacon function thatmaintains a connectivity state with the overall system and allows fordata to be telemetered. Generally and according to this embodiment, thebeacon may be generated in two ways: either by the personal statusmonitoring device 10 in periodic fashion or in response to a specificrequest by the central server 30 or the personal gateway device 20.According to the present embodiment, the beacon is set preferably to aperiodic pattern that allows overall systems maintenance at an optimizedlow power consumption using the radios that are contained in themonitoring device 10 and a personal gateway device 20 a, b, c,respectively. It should be noted that a preferred goal of the hereindescribed system is to produce an optimized battery life for thepersonal status monitoring device 10 that is equivalent to greater thanninety percent of the duration of a hospital stay or one week, whichever is longer. Additionally and according to another aspect of theinvention, the periodicity of beacon patterns being transmitted can beprogrammed in order to encode the type of physiologic parameter that isbeing monitored by each personal status monitoring device 10. Forexample, an “ECG-only” beacon such as the present embodiment may have apreprogrammed repetitive rate of one beacon transmission about every 2seconds, whereas a “respiration rate” beacon from a separate personalstatus monitoring device 10 may have a beacon repetition rate of onebeacon transmission every 11 seconds. Other similar encoding schemes mayalso be used for the same purpose.

Fundamental to low power consumption goal of the present invention isthat it is intended that only primitive physiologic data such as R-Rintervals, (in the case of ECG electrodes) battery status, and otherhigh level indicators of either physiologic or device data arepreferably embedded for periodic transmission within the beacon.

The beacon is generated by a low-power transceiver, preferablystandards-based, using, for example, 802.15.4 standard (although itshould be readily apparent that other radios with comparable performancecan be substituted). As noted, this transceiver is normally andpredominantly in the “OFF” state. That is, the sensor continuouslydetects on the patient, but the beacon only transmits at its programmedintervals to the personal gateway device in “normal” state in which thenetwork is predominantly off.

At least one indicator can be optionally provided with each personalstatus monitoring device 10. To that end, an LED or LCD status indicatorcan be used to determine whether the monitoring device 10 is operationaland whether the communication link with the personal gateway device 20is active. In addition, the status indicator can also indicate by visualmeans whether context management (e.g., binding of the continuousphysiologic signal, hardware ID 209, 524, FIG. 4, and the unique patientidentifier 206) has been established or is being maintained. In lieu ofor in combination with a visual means, an audio transducer, such as atleast one of an LED and/or LCDs, can also be used; Each of theseindicators may also be used to annunciate alarm conditions.

More particularly and in terms of overall signal processing, thepersonal status monitoring device according to this embodiment performsthe following tasks. Each of the following tasks relate to the specificembodiment, wherein event detection is only triggered based on ECGmeasurement as the primary physiologic parameter.

-   -   i) Heart beat detection, based on the detection of an ECG QRS        complex. As noted above, an additional acoustic channel may be        employed in the personal status monitoring device 10 of the        present embodiment to detect cardiac sounds;    -   ii) Heart rate or R-R interval measurements;    -   iii) Programmable high/low heart rate threshold crossing;    -   iv) Event detection, such as VTACH, Vfib, asystole;    -   v) Heart rate variability detection, for example, atrial        fibrillation;    -   vi) Motion or patient activity detection using the accelerometry        channel; and    -   vii) pacer detection.

In addition, data compression is also performed in the personal statusmonitoring device 10 in order to preserve the RF power, preferably usinga non-linear data compression scheme, though others could be similarlycontemplated. A beat detector can be used such as those commonly knownin the field to a matched filter (MF) that operates on the sampled datain order to determine heartbeats and fiducial points. The fiducialpoints are used in order to bracket the PQRS complex and to determinethe R-R interval. These intervals can then be compressed by means knownto those skilled in the field.

Waveform data can also be compressed. ECG signal data is sampled at anappropriate Nyquist rate (e.g., 200 s/s). The extracted waveform beat isthen compressed, using lossy or lossless compression techniques. Theresulting compressed ECG sensor data is assembled in a packet fortransfer across the RF link either in the beacon or on a periodic basisdepending on the tradeoff of microcontroller power consumption for datacompression versus RF section power consumption for transfer to thepersonal gateway device 20. Similar data compression schemes may beapplied to other physiologic sensors.

With regard to the linkage between the personal-status monitoring device10 and the intermediary personal gateway device 20, it is further notedthat the personal gateway device 20 is linked bidirectionally accordingto this embodiment, to the central server 30 as described in greaterdetail below. Preferably and among other advantages, this linkagepermits the personal status monitoring device 10 to download at leastone program library from the central server 30. This downloadingcapability allows the microprocessor 202 of the personal statusmonitoring device 10 to be programmed with the most recent algorithms,for event detection, signal processing, data compression, etc., that areavailable to the central server 30, for example, upon connection to thepatient or alternatively upon demand.

As noted and shown in FIG. 2, the personal status monitoring device 10wirelessly communicates over the low-power (WPAN) network 24 with thepersonal gateway device 20 a, 20 b, 20 c via a low cost, low power,preferably standards-based transceiver, using, for example, the IEEE802.15.4 standard (although it should be readily apparent that otherradios can be substituted). Data display, trend storage, additionalsignal processing and wireless relay of data originally transmitted tothe gateway device by the personal status monitoring device subsequentlyto the central server 30 a, 30 b are tasks that are preferably performedby the personal gateway device 20 a, 20 b, 20 c which is now describedin greater detail.

At the outset, the personal gateway device 20 a, 20 b, 20 c is alsopreferably designed to be embodied in a number of form factors, forexample, and as noted a PDA, cellular phone, or other suitable design,such as a patient-worn version, depending, for example, on marketattractiveness and other factors. The personal gateway device 20preferably contains a compatible transceiver to that contained withinthe personal status monitoring device 10 for permitting bi-directionalcommunication therewith over the personal area network 24.

According to the present embodiment, the personal gateway device 20 alsopreferably performs additional signal processing and statisticalanalysis in order to qualify events that are received from the personalstatus monitoring device 10 as true positive event candidates. Truepositive event candidates, as qualified by the personal gateway device20, subsequently are relayed to the central server 30 a through a mediumor long range bi-directional wireless link 28 a, 28 b, preferablystandards based, such as, for example, IEEE 802.11x for medium range 28a or alternatively any suitable cellular phone standards 28 b. Thegateway personal device 20 further provides a periodic beacon via acontained WLAN/WAN transceiver or radio in order to maintainconnectivity with the central server 30. The intermediary gateway device20 of this embodiment has greater power resources than the personalstatus monitoring device 10 and therefore permits greater data storageprior to accessing the server via an access point (not shown) of thenetwork 28 a, 28 b. Therefore, the gateway device 20 serves as a bufferprior to transmission of same to the central server 30. As in thepreceding, the beacon maintains network connectivity of the hereindescribed system in which the state of the system is normally andpredominantly “off” with the exception of the periodic beacontransmissions in spite of the fact that the sensors on the patientstatus monitoring device are continually monitoring the patient. Forexample, the beacon rate of the personal status monitoring device 10 canbe on the order of about one transmission for each 5 seconds in which atransmission length is about 0.2 seconds and the personal gateway device20 may have a beacon transmission rate of about one transmission everytwo minutes to the central server in which the transmission length isabout 0.5 seconds. The preceding periods are provided to give the readerthe overall impression of the normal “quiet” state of the hereindescribed system.

In addition to the above features, a separate location radio 550provides an additional beacon to a separate wireless infra structure,such as is provided by Radianse Corp. or similar technology. Thisseparate beacon provides a redundant means for transferring patient datainformation to the central server 30 and establishing networkconnectivity in a predominantly “off” or “quiet” state.

Referring to FIGS. 2 and 4, a primary function of the personal gatewaydevice 20 is to act as a radio relay repeater from the personal statusmonitoring device 10 to the central server 30 through an intermediary RFlink. In the case of in-building use by the system, an IEEE 802.11xradio technology is preferably utilized. WiFi (IEEE 802.11b) ispreferred at the present time due to the overall pervasiveness of thisradio standard in healthcare IT settings. As IT organizations maymigrate to other standards based radios, such as IEEE 802.11(a) or (g)however, it will be readily apparent that other device configurationscan alternatively be used. In the case of out-of-building use, theintermediate radio of the personal gateway device 20 is preferably basedupon available cellular phone technologies, such as GSM, TDMA, CDMA, orG3, depending on local availability and coverage. Additionally, thepersonal gateway device 20 also preferably provides interim signalprocessing, pattern recognition, status indication and user actuation.The interim signal processing is provided preferably in a distributedmanner relative to the sensitivity of the personal status monitoringdevice 10. By that, it is intended that the sensitivity of theprocessing of the gateway device 20 will eliminate additional falsepositives that were not eliminated by the personal status monitoringdevice 10.

As noted, the physical shape and mechanical design of the intermediarypersonal gateway device 20 is intended to assume a variety of multipleforms; for example, a neck-worn pendant, a badge form factor attached toa hospital gown, a clothing attachable tag, or a wrist worn bracelet,among others, the device in any event being configured for attachment tothe patient with the overall design preferably being fairly simple andeasy to utilize. Preferably, the wearability of the device 20 is modeledaround that of long-term wear jewelry. In addition, the overall designof the personal gateway device 20 is durable as conventional monitors,is disinfectable, and is able to be worn by the patient, for example, ina shower. As with the personal status monitoring device 10, the personalgateway device 20 is preferably programmed with a unique (hardware)identification number 524, FIG. 4, that is stored in a non-volatilememory device 522, FIG. 4, and is preferably also denoted on theexterior surface of the device 20, preferably in at least one of abarcode and/or human-readable form.

The personal gateway device 20 of the present system has at least threeprimary functions, namely: to serve as an embedded radio coordinator, toserve as a secondary signal processor with regard to physiologic data,and further to provide a primitive information display as well as act asan input device. The personal gateway device 20 is preferably powered byeither disposable or rechargeable batteries.

Referring to FIG. 4, a schematic diagram is provided wherein a pluralityof contained transceivers or radios 500, 530, 540, 550 permit the relayof. information between one another in a coordinated method through acontained microcontroller 520. These radios 500, 530, 540, 550 maycontain one or more semiconductor chips. It should be readily apparentthat additional radios or other wireless communications mean, such asfor example, IrDA means, may be added to the present design.Furthermore, the microcontroller 520 may be embedded in one or more ofthe radios 500, 530, 540. These radios may also be combined integrallyas silicon components become available.

The outputs of the radios 500, 530, 540, 550 are coupled to antennas501, 531, 541, 551 respectively. These antennas 501, 531, 541, 551 maybe combined to fewer structures in the case where the same spectrum isused by more than one radio. Parts or all of the radios 500, 530, 540,550 may be combined where they share design similarities.

The embodiment illustrated in FIG. 4 provides communication relaysbetween a WLAN radio 500 based on IEEE 802.11, (a), (b), or (g),depending on the facility infrastructure, in which the radio operatesand the Personal Area Network 24, FIG. 2. Selected radios may containmore than one of these standards. An alternative radio for out ofbuilding use is based on WAN technologies, such as TDMA, CDMA, GSM, orG3 depending on local service provisions.

WPAN radio 530, according to this embodiment, provides two-directionalcommunications between one or more personal status monitoring devices 10to and from other devices connected through radios 500 and 540.Alternate radios, for example, such as those found in devicesmanufactured by Fitsense, Corp. may be substituted. In addition, anultra short-range radio 540 is provided in order to read an RFID tag(not shown) attached to the patient, the tag containing demographic orother patient-related information. Other short range, non-standardsbased radios may also be utilized for this purpose.

Power management for the personal gateway device 20 is represented bycomponents 511-513. The personal gateway device 20 preferably includes arechargeable battery 513 having a useful life of over 5 days, orapproximately equivalent to that of an average expected patient lengthof stay in a hospital. Longer battery life is highly desirable. Chargingmeans is provided through a power supply circuit 512 that generates DCpower from RF power, AC mains, or by harnessing mechanical, bodythermal, or solar power 511 as is found for example, in digitalwristwatches and known to those skilled in the art. Alternatively, aseparate charging mechanism can be employed as commonly known to thoseof sufficient skill in the field. Power supply 512 regulates charging ofthe battery 513 and supplies power requirements to the components of thepersonal gateway device 20. Preferably, the battery 513 can be rechargedto full storage in less than eight hours (e.g., overnight) when chargedby AC mains or is trickle charged at a rate higher than powerdissipation when harnessing other power sources.

A microcontroller 520 provides routing control of radios 500, 530, 540,550 secondary signal processing and pattern recognition, and userinterface through a display 529 that can be optionally provided with thedevice. In addition, at least one audible annunciator 527, and one ormore visible indicators, such as LEDs 528, which may be combined withthe audible annunciator 527, and one or multiple input actuators 525 toprovide local alarm notification, as well as to provide an indication ofconnectivity status, and in the case of the visual display, patientidentification, messaging from the central server 30 and personal statusmonitoring device 10. Display 529 may be used to display physiologicdata from the sensors of the monitoring device 10. It will beappreciated that some or all of the above user interfaces can beimplemented into the personal gateway device 20. Preferred embodimentsmay further include an audio and visible annunciator means only. Theaudible annunciator 527 is preferably required for the personal gatewaydevice 20 to provide alarm annunciation in proximity to the patient(e.g., in the event the personal status monitoring device 10 does nothave any alarm annunciation capability or in the instance that an alarmevent occurs and the personal gateway device 20 loses communication withthe central server 30).

The contained microcontroller 520, according to this embodiment, has anassociated volatile memory device 521 and a non-volatile memory device522. Preferably embedded in non-volatile memory device 522 at the timeof manufacture is a unique identification number 524. Patientidentification at the time of initially synching the device inconnection with the personal status monitoring device 20, can be storedin non-volatile memory device 522 through any available input, such as,for example, manually by means of a barcode reader (not shown) or othersuitable means, that can be utilized or biometric input 545. Accordingto the present invention, the later obtained unique patient identifier206 remains stored for as long as there is positive confirmation ofconnectivity to at least one of patient connected personal statusmonitoring device 10 and the device is receiving continuous patient data(at least one continuous physiologic signal); that is to say, thepersonal status monitoring device 10 remains attached to the patient,the device remains powered, etc. in a binding manner as previously notedin connection with the personal status monitoring device 10, therebyproviding patient context management.

The microcontroller 520 of the personal gateway device 20 furtherpreferably includes software in order to perform tasks that are specificto the system function. According to a preferred embodiment, theseapplications are written in applications modules (using, for example,Java script) that permit easy downloading of same from the centralserver 30 a, 30 b. These applications include, for example, encryptionand authentication software that secure's and protects patientconfidentiality of data.

A preferred embodiment of the software architecture for the personalgateway device 20 is illustrated in FIG. 5. It should be noted that thepresent architecture is exemplary and that other architectures known tothose skilled in the art that achieve the same function may besubstituted. Software coordination is organized and then is coordinatedthrough a Comms Object 401.

Signal Processing Object 404 receives data from any of networkedpersonal status monitoring devices 10 through the WPAN radio 530 andperforms intermediate signal processing and pattern recognition. Theprimary purpose of the Signal Processing Object 404 is to providefurther qualification of events that have been initially triggered bythe personal status monitoring device 10 in order to reduce theincidence of false alarm events from passing onto the central server 30through WAN/WLAN radio 420 and thereby reduce power consumption of thebattery 513 that is contained in the personal gateway device 20. Theintermediate signal processing optimizes the normal and predominant“off” state of the interconnected network by determining and controllingperiodic beacon events between the personal gateway device 20 and thecentral server 30, which further reduces power consumption of thepersonal gateway device. Power management for the personal gatewaydevice 20 is controlled through Resource Management Object 405, whichalso manages other resources, such as, but not limited to,microprocessor sleep status, task execution and priority, internaldiagnostics and other resources.

Events are displayed or annunciated through UI object (user interface)410 for local alarm and/or alerts through rules that are provided inAlarm Annunciation object 402 or from the server 30. Alarm Annunciationobject 402 determines the priority of alarm and alert events, durationof annunciation and targeted annunciator (audible, visual, display,combination, and other) shown as 532.

Data from various internal and external sources are stored in thepersonal gateway device 20 through Data Stores Object 403. This dataincludes, but is not limited too, beacon patient data, event storage,including a snapshot of any raw physiologic waveforms, the last “N”events, where “N” is user-selectable, journaling data captured by thepersonal gateway device 20, and other suitable data relating to thepatient to which the gateway device is connected, as well as localperformance data.

Radio modules 500, 530, 540, 550 communicate with Comms Object 400through Applications Program Interfaces (API) to Comms Object 401 toroute data to other Objects. It is generally understood that the WPANradio 530 provides connectivity to one or more personal statusmonitoring devices 10, the RFID radio 540 provides connectivity to apatient worn identification tag device. The WAN/WLAN radio 500 providesconnectivity to the central server 30 and the wireless location radio550 provides location capability and additional context management thatrelates the condition of the patient provided by one or more sensors tothe environmental location of the patient. For example, location radio550 may determine whether a patient is in a hospital bedroom orprocedures room. This context data can be used to associate withspecific patient care plans.

According to this embodiment, the central server 30 a, 30 b performs thefunctions of device management, providing rules sets or engines for thedistribution and escalation of messages and data transfer to therespondent devices 40 a, 40 b, database management, client displayrendering, interface in Clinical Information Systems (CIS) or ElectronicMedical Records (EMR), web hosting of data, final determination of truepositive events, indoor location mapping, and other software activitiesthat may require greater processing power, storage or communicationsthat is not possible in either the personal status monitoring device 10or the personal gateway device 20. Interface to a known centralmonitoring station, such as, for example, the Acuity™ monitoring stationmanufactured by Welch Allyn, Inc. is preferred in that this interfaceallows the integration of the presently described Monitoring Networksand devices in such a way that the systems complement each other.However, an interface to a physiologic monitoring station is not anecessary requirement. The central server 30 a, including its database30 b, is architected to be low cost in its minimal configuration, yet isscalable as devices and applications expand.

The hardware of the central server 30 is preferably based on the mostcost effective yet scalable hardware platform. Intel based personalcomputers are a primary candidate due to cost. Linux is a primaryoperating system (OS) candidate for similar cost considerations.However, other hardware and software operating systems will beconsidered if they offer a cost effective alternative or there are otherbusiness compelling reasons to consider.

The central server 30 is preferably a low cost entry platform that isrelatively easy to manufacture, configure and install. Preferably, thecentral server 30 includes graphical user interfaces (GUIs) that canutilize existing customer desktop computers running, for exampleMicrosoft (OS) and having accessible web browsers.

The central server 30 also preferably includes an optional interface toan existing central monitoring station, such as, for example, the Acuitymonitoring Station manufactured by Welch Allyn, Inc., serving as aninstalled base wherein the server offers features that link therespondent devices to the installed base as well also preferablyoffering a mobile patient ID.

The central server 30 also preferably supports mobile computingplatforms, such as select mobile phones, PDAs running Microsoft or PalmOS that support extensible interfaces, such as, for example, compactFlash.

As to the task specifics handled by the central server 30, the centralserver is responsible for management of patient names/identificationsand respondent device assignments. The central server 30 also acts as arepository for patient data storage as transmitted, either by theperiodic beacon of the personal gateway device 20, by eventtransmission, and/or through specific request. This data can be storedpreferably for a predetermined time (e.g., 10 days), the data typicallyincluding static waveforms and numeric data as conveyed originally fromthe personal status monitoring device 10, though compressed continuousdata can also be stored depending on the extent of data compression inthe device 10, as noted previously.

The central server 30 according to the present embodiment can alsoprovide alarm annunciation, for example, either through a textualdisplay of alarm or alert event with a segment of waveform displayedand/or audible signals or both.

Tabular or graphical trends can be displayed or outputted using thecentral server 30 in a manner that is similar or equivalent to thosefound, for example, on central stations such as the Acuity centralmonitoring station manufactured by Welch Allyn, Inc. In addition, theserver 30 can also preferably provide output via print capabilities onany connected PCs or separate peripheral device.

In terms of output, a static ECG waveform (not shown) can be displayedby the central server 30, if supported by the personal status monitoringdevice 10. Preferably, the server 30 also maintains separate interfacesto Clinical Information Systems (CIS) or Electronic Medical Records(EMR) warehouses and is extendable to support other wireless products.

Display rendering on the respondent device 40 is preferably downloadablefrom the central server 30 using, for example, Java beans, applets, orother suitable software transfer methods. Data is transferred preferablyto the respondent device 40 a, 40 b using XML with suitable data typesand style sheets, though other software means may also be used as isgenerally known to one skilled in the field.

As has been noted throughout this discussion, battery operating time isan important consideration of the herein described system. Furthermore,and in the case of respondent devices that comprise either a PDA or acellular phone, the ability to wake up and pre-empt other applicationsupon receipt of a message is an important design consideration.Therefore, an alarm message will take priority over applications in useor the at least one respondent device 40 a, 40 b at the time an alarmmessage is received. It is recognized that PDA operating systems must beconsidered as well. Preferred features of the respondent device(s) 40include the following:

The respondent devices 40 a, 40 b according to the present embodimenteach provides means for user (nurse, physician, etc.) authentication inorder to access patient-related data (to satisfy standards such asHIPPA). In addition, the respondent device 40 a, 40 b includes agraphical user interface that allows entry of patient-related data overthe bi-directional link into the personal status monitoring device 10.

The respondent device 40 a, 40 b according to this embodiment includes apatient context manager. This context manager communicates with thepersonal status monitoring device 10, via a network (in order to performbinding and context management). The manager admits, initiates, personalstatus monitoring device patient ID and other unique patient contextfields, and views patient context. The respondent device 40 a, 40 b alsopreferably includes a clinical administrative manager. This managerincludes a register respondent responsible for patients and allowsacknowledgment of alarms.

A personal status monitoring device data display indicates patient ID,name, current data, patient location, stored data in columnar tabularformat as well as an alarm condition (auto open) with current numericsand sampled waveform (if available from the personal status monitoringdevice).

It will be readily apparent that the above features of the respondentdevice 40 a, 40 b can be expanded with the addition of parameters, asnew patient status monitoring devices are conceived (for example NIBP,pulse oximetry). Expansion of the graphical user interface is animprovement well within the intended purview of the invention.

The software architecture of the respondent device 40 is relativelysimple. Regardless of the platform, the at least one respondent device40 is essentially a lightweight client whose primary purpose consists oftwo activities:

First, the respondent device 40 is intended to display informationtransmitted to it by the central server 30, including alarm annunciationvia speaker and data display on the respondent device. Secondly, the atleast one respondent device 40 is intended to read and transmitclinician input back to the central server 30.

All of the functionality of the respondent device 40 noted in theprevious section falls into one of these categories, and can be carriedout using an appropriately equipped browser that is preferably providedon the respondent device 40 a, 40 b or other suitable means known tothose skilled in the art.

This lightweight implementation shifts the burden of data acquisitionand formatting from the respondent device 40 a, 40 b onto the centralserver 30, from which the respondent device obtains its information.

It should be apparent that there are other variations and modificationsthat are possible within the intended scope of the invention. Onepossible network configuration is illustrated in FIG. 6, wherein anumber of patients 21 are configured, each with monitoring devices (notshown), that are connected via the personal network (WPAN) to arespective gateway device (not shown). Each of the gateway devices isconnected to a server node 31, serving the overall functionality of thecentral server discussed previously. In this instance, a plurality ofserver nodes 31 are disposed in order to increase capacity. Thisconfiguration would be particularly useful in those environments inwhich a large number of patients 21 are to be monitored. For purposes ofthis description, “N” number of server nodes 31 are provided, eachserver node being configured for handling a block of patients 21.

For example, a set of patients (e.g., beds), each being equipped withbody-worn patient status monitoring devices 10, FIG. 1, and intermediary(e.g., gateway) devices 20, FIG. 1, as described above, or a hospitalfloor having a predetermined number of patients with same would beassigned to a specific server node 31, wherein the assigned server nodewould monitor those patients (with regard to event detection). If theload increases, additional server nodes 31 could be added to handle thisblock of patients. In this manner, the system scales in order to moreeffectively handle a greater number of patients. Optionally, any or eachof the server nodes 31 of the herein described system could also workcooperatively, as shown by line 33, thereby sharing data or otherresources 35 as needed. The shared resources 35 can include, forexample, nurse/caregiver assignments, printers, and an HIS/CISinterface, among other resources.

With the preceding background and detail concerning the above system andits architecture, the following use case scenario herein summarizes oneintended functionality and purpose of the described system as depictedin FIG. 2. A patient experiences chest pains and is transported to ahospital emergency department. Upon arrival at the emergency department,a clinical technician places a patient status monitoring device 10 onthe patient's body over the left chest (e.g., over the heart) and strapsa personal gateway device 20 a on the patient's arm. The patient statusmonitoring device 10 nitiates linkage to the personal gateway device 20a via the PAN 24 and upon completion of linkage, indicators 107, FIG. 3,and 528, FIG. 5, respectively, display successful communications havebeen established therebetween. The patient status monitoring device 10simultaneous to its linkage with the personal gateway device 20 a,begins measuring and analyzing the patient's ECG and sending HR and R-Rvalues to the personal gateway device 20 a over a periodic beaconthrough the wireless PAN 24. The personal gateway device 20 a in turn,communicates to the central server 30 a through a Wireless Local AreaNetwork (WLAN) 28 a and establishes a database 30 b of heartrate (HR)and R-R interval values.

In the meantime, the technician enters patient identification data andpatient specific alarm settings into a respondent device 40 a.Identification data and alarm settings are communicated to the centralserver 30 a over the WLAN link 28 a to the database 30 b where a uniquepatient identifier 206 is assigned. Alarm settings and the uniquepatient identifier 206 are down loaded to the personal gateway device 20a over the WLAN 28 a for storage in the gateway device and downloadedfrom the personal gateway device 20 a for storage in the patient statusmonitoring device 10. Subsequent transmissions of beacons from thepersonal status monitoring device 10 and the personal gateway device 20a to the central server 30 a are embedded with the unique patientidentifier 206, FIGS. 3, 4, and the hardware identifiers 209, FIG. 3,and 524, FIG. 4. Other embodiments may not need to append hardwareidentifies since this capability may be embedded in communicationprotocols, such as TCP/IP. The combination of the unique patientidentifier 206, the separate hardware identifiers 209, 524, FIGS. 3, 4,respectively and the continuous detection of physiologic data causes thesystem between patient and the central server 30 a to be “bound”.

The herein described system operates in a normally off state. That is,beacons between the patient status monitoring device 10 and the personalgateway device 20 a over the first wireless link/network 24, and secondbeacons between the personal gateway device 20 a and the central server30 a over the second wireless network 28 a are set to the longestpossible interval, while maintaining a positive communication linkbetween the patient status monitoring device 10 and the central server30 a in order to preserve battery energy of each of the patient statusmonitoring device 10 and the intermediary personal gateway device 20 a.Care providers may view patient data from a variety of displays,including those provided on respondent devices 40 a, 40 b, or displaysconnected to the network such as laptops 6 a, PCs 6 b or printers 6 c.

The central server 30 a stores caregiver patient assignments andcaregiver to respondent device assignments in the database 30 b. Suchassignments may be used to route patient data to specific respondentdevices 40 a, 40 b. The central server 30 a may contain rules sets thatallow escalation of alarm notification in the case where the first orprimary (assigned) respondent device 40 a, 40 b is not available withina prescribed time.

In the event that the patient experiences an alarm event, the patientstatus monitoring device 10 immediately communicates data, including butnot limited to physiologic waveforms, cause of alarms and otherpertinent data to the personal gateway device 20 a. Signal processing404, FIG. 5, further analyses data to reduce alarms caused by artifacts.True positive alarms are sent over the second wireless network (WLAN) 28a to the central server 30 a. The central server 30 a matches patientidentifier with an assigned respondent and sends alarm data to arespondent device 40 a over the second wireless link 28 a. The centralserver 30 a may communicate alarm to more than one respondent device 40a, 40 b. The care giver may acknowledge the alarm via the respondentdevice 40 a, 40 b to silence or suspend the alarm.

Included in the system is a means for locating the patient statusmonitoring device 10, the personal gateway device 20 a, and/or therespondent device 40 a through a location device 550, FIG. 5. Thelocation device 550, may also be embedded in the personal statusmonitoring device 10 and the respondent device 40 a in addition to theintermediary device, as shown herein. Location device 550, FIG. 5,transmits a beacon to location receivers which are linked to the centralserver 30 a. The central server 30 a determines location coordinates orother location identification for communication to at least onerespondent device 40 a, 40 b. In the event of an alarm, locationinformation is sent to the respondent devices 40 a, 40 b. Similarly, thelocation device 550 can identify when the patient is transferred fromone area of the hospital or other health care facility to another.

Upon discharge from the hospital, the patient can exchange the personalgateway device 20 a which may be limited to a Wireless Local AreaNetwork (WLAN) 28 a with a personal gateway device, such as aprogrammable cellular phone 20 c, that is capable of communicationacross a Wide Area Network (WAN) 28 b. Furthermore, as know to thoseskilled in the art, the personal gateway devices 20 a, 20 c may havecapabilities for both WLAN 28 a and WAN 28 b.

While the present invention has been particularly shown and describedwith reference to the preferred mode as illustrated in the drawing, itwill be understood by one skilled in the art that various changes indetail may be effected therein without departing from the spirit andscope of the invention as described by the following claims.

1. A method for performing context management, said method comprisingthe steps of: producing a continuous physiologic signal, as detected bya monitoring device; associating at least one unique hardware identifierto said monitoring device; creating and associating a unique patientidentifier from said hardware identifier; and binding said uniquepatient identifier to said continuous signal wherein a change in saidphysiologic signal in which said signal is no longer continuous willcause the unique patient identifier to automatically unbind from saidsignal, said unique patient identifier remaining unbound even afterresumption of a continuous signal until each of said producing,associating, creating and binding steps are repeated.
 2. A methodaccording to claim 1, wherein the source of said patient identifier is abiometric input.
 3. A method according to claim 1, wherein the source ofsaid patient identifier is an RFID tag.
 4. A method according to claim1, including the additional step of identifying said patient prior tosaid associating step and storing the identity of said patient, whereinsaid patient identity and said patient identifier are separateidentifiers.
 5. A method for performing patient to device contextmanagement comprising the steps of: producing a continuous physiologicsignal from a patient, as detected by a monitoring device; associating aunique monitoring device identifier with a newly created unique patientidentifier; appending said newly created unique patient identifier tosaid continuous physiologic signal, wherein a change in said physiologicsignal in which said signal is no longer continuous will automaticallycause the unique patient identifier to disassociate from said signal,said identifier remaining unbound until said appending step is repeated.6. A method according to claim 5, wherein said associating step includesthe associating of more than one device identifier prior to saidappending step.
 7. A method according to claim 5, wherein theassociation of said created unique patient identifier and patientidentity is secret.
 8. A method according to claim 5, including theadditional step of identifying said patient prior to said associatingstep and storing the identity of said patient, wherein said patientidentity and said patient identifier are separate identifiers.
 9. Amethod for protecting privacy of patient information comprising thesteps of: producing a continuous physiologic signal, as detected by amonitoring device; creating a unique monitoring device identifier;creating a unique patient identifier, said identifier being createdremotely from said monitoring device; associating said monitoring deviceidentifier with said unique patient identifier, said associating stepbeing done remotely from said monitoring device; and appending saidunique patient identifier to said continuous physiologic signal whereinthe association between patient identity and said unique patientidentifier is secret.
 10. A method for performing patient to caregivercontext management comprising the steps of: associating at least oneunique monitoring device identifier with a unique patient identifier;associating a unique respondent device identifier to a unique caregiveridentifier; associating said at least one unique monitoring deviceidentifier to at least one unique respondent device identifier therebyassociating at least one unique caregiver identifier to at least onesaid unique patient identifier; and accessing a stored rules set in theevent a primary respondent device is unavailable in order to permit atleast one secondary respondent device to receive an alarm notificationfrom a monitoring device.
 11. A method according to claim 10, includinga plurality of caregivers, each said caregiver having a unique caregiveridentifier.
 12. A method according to claim 10, including the step ofassociating each of said caregivers with said respondent deviceidentifiers simultaneously.
 13. A method for performing patient toenvironment context management comprising the steps of: producing acontinuous physiologic signal of a patient, as detected by a monitoringdevice; associating a unique monitoring device identifier to a newlycreated unique patient identifier; appending said unique patientidentifier to said continuous physiologic signal; associating a uniquelocation device identifier to at least one unique monitoring deviceidentifier thereby associating a patient location to said unique patientidentifier wherein a change in said continuous signal causes the patientidentifier to automatically and permanently become unbound.
 14. A methodaccording to claim 13, including the additional step of identifying saidpatient prior to said identifier associating step and storing theidentity of said patient, wherein said patient identity and said patientidentifier are separate identifiers.